Typically, chlorine is added to a city's water supply to kill pathogens that are harmful to humans. Once the pathogens are killed, the water is fit for human consumption.
However, not all water is consumed. City water supply systems are routinely flushed and flow tested to remove debris from the water mains and to determine water availability for fire fighting. Fire pumps that are used to boost the water supply of fire sprinkler systems are flow tested annually as an insurance requirement and/or local fire code requirement. In all of these cases large amounts of chlorinated water are discharged to storm sewers back into the environment or into a waste-stream. Because chlorine is toxic to aquatic life, before the water can be discharged, it must be dechlorinated, making it safe for the environment. The Federal Clean Water Act (“CWA”) prohibits the discharging of water that contains toxic pollutants, including chlorine, in toxic amounts. The U.S. Environmental Protection Agency (“USEPA”) establishes the allowable levels of pollutants. Other state and local jurisdictions may provide additional restrictions. Enforcement includes fines and possible incarceration.
Dechlorination can be accomplished by adding to the discharging water, absorbic acid, sodium sulfite, sodium bisulphate or any other chemical that reacts with chlorine ions in such a way that the fluid is no longer toxic to aquatic life, or meets otherwise required standards for discharge.
Typically, dechorination agents are added to a basin containing chlorinated water. However, in many situations, a basin is not provided, or would be impractical due to size, portability and locality. In these cases the dechlorination agent must be added to the chlorinated stream before the stream is discharged into the environment. Therefore, a device that does not require a basin for adding a dechlorination agent would be beneficial for locations where a basin is undesirable or impracticable.
A portable system is extremely advantageous for discharging chlorinated water where a permanent or semi-permanent dechlorinating operation is not desired. This includes situations such as draining a system, testing fire pumps, and discharging water from a fire-main whether as a one-time, infrequent, or even frequent event.
Where local regulations require dechlorination, the above tasks would normally require the water to be collected, transported offsite, and treated elsewhere, all at a great expense. Failure to comply could result in fines, and in some cases, criminal charges, not to mention the adverse affects to aquatic life and groundwater supplies that will occur if the water is not properly treated.
A dechlorination device that does not require a basin, is portable, temporary, and controllable, would save costs, time, effort, and prevent possible regulatory action against the discharger of chlorinated water would be beneficial. Such a device is the subject of the current invention.
U.S. Pat. No. 5,405,540 to Tang, issued on Apr. 11, 1995, discloses a method for treatment of wastewater. The apparatus is a combination chlorinator and dechlorinator. Chlorinated water washes over dechlorinating tablets. The dechlorinating tablet container is partially submerged in a contact tank. Unlike the present invention, a tank is required. Hence, the Tang invention is not portable and could not be transported by one individual to a site for operation. In addition, the Tang invention does not allow for an operator to set the proportional flow rate across the tablets as the present invention does. Also, the present invention can be completely valved off such that the proportional flow rate is zero.
U.S. Pat. No. 5,350,512 to Tang, issued on Sep. 27, 1994, discloses an apparatus for treatment of wastewater. This invention is virtually identical to U.S. Pat. No. 5,405,540 issued to Tang, discussed in the proceeding paragraph. However, what is claimed in this invention is the apparatus as opposed to the method.
U.S. Pat. No. 6,298,871 to Pickens et al., issued on Oct. 9, 2001, discloses a chemical feeder. The feeder may be placed in a piping system. A connection for an inlet and outlet are provided. A liquid fluid enters the feeder. A predetermined flow pattern is designed within the feeder. The fluid flows across a liquid-soluble chemical. A portion of the chemical is dissolved. The chemical containing fluid exits the feeder. In this invention, there is a full flow of liquid across the solid chemical, whereas the present invention only requires a proportional flow of the fluid across the solid chemical. In addition, the feeder of Pickens et al. is designed for a flow rate between 0.2 and 10 gallons per minute. The present invention is designed for much greater flow rates, such as those flow rates that are required by the National Fire Protection Association for testing fire pumps and fire flow testing for fire mains, as well as main flushing requirements (for debris removal) as recommended by the American Water Works Association. In addition, the present invention can be valved off such that there is no flow across the treating agent when no treating agent is required, without requiring the removal of the solid chemical. This allows for conservation of the treating agent itself.
U.S. Pat. No. 6,221,257 to Grim, issued on Apr. 24, 2001, discloses a fluid treating apparatus. A reaction container containing a treating agent is inserted into the apparatus. Unlike the present invention, the Grim invention operates by directing the full stream of the fluid flow across the container. As discussed above, the present invention can be valved off such that there is no flow across the chemicals when no chemicals are required without requiring the removal of the solid chemical. Additionally, the present invention only requires a proportional flow when operating.
U.S. Pat. No. 6,138,703 to Ferguson et al., issued on Oct. 31, 2000, discloses a chemical feeder. The feeder has a single opening in the base where it is connected to a fluid flow. In order for fluid to enter the feeder, pressure in the fluid stream must be greater than the pressure in the feeder. The present invention utilizes an inlet and an outlet, thereby diverting proportional fluid flow through the dechlorination agent reservoir. In addition, the device in the present invention can operate at any system pressure as long as there is pressure attributed to velocity head, which will create fluid diversion attributed by the design of the device, and the system pressure does not exceed safety ratings.
U.S. Pat. No. 6,264,846 to Smith, issued on Jul. 31, 2001, discloses a system for processing water by mixing the water with an additive. Fluid flows through a by-pass where a chemical is injected into the fluid. To motivate flow through the by-pass, a restriction that causes a pressure drop in the main flow, thereby forcing flow through the by-pass, is placed in the main flow of the fluid. The present invention does not require a restricting device to divert flow through the by-pass, nor does the present invention obstruct the flow-path as the '846 patent does. Therefore, there is less energy consumption of the pump and more control over any test equipment. In addition, the present invention does not require a device to inject the chemical into the fluid.